1. Field of the Invention
The present invention relates to an electric bending endoscope which electrically bends a bending portion of an inserting portion.
2. Description of the Related Art
Recently, an endoscope is widely used. Various curing treatments are performed by inserting an elongated inserting portion in the celom so as to observe the organ in the celom or by using a treatment tool inserted in a therapeutic instrument channel as needed. In the industrial field, the endoscope observes and examines inner scratches and corrosion of a steam generator, a turbine, an engine and a chemical plant by inserting an elongated inserting portion.
The endoscope has a bending portion which is freely bent on a base end side of an edge portion in the elongated inserting portion. Further, the endoscope receives an instruction as the amount of bending, corresponding to a bending position or a bending speed of the bending portion, by means for inputting a bending operation such as a bending operation lever or a joystick arranged to an operating portion. In the endoscope, a bending operation wire is mechanically stretched or contracted based on the amount of bending inputted as the instruction so as to bend the bending portion.
The above-mentioned endoscope includes an electric bending endoscope in views of the operability. For example, Japanese Unexamined Patent Application Publication No. 2-159243 discloses one of the above-mentioned electric bending endoscopes, in which a built-in motor as bending driving means is controlled for rotation, the motor's driving force enables a bending operation wire to stretch or contract, and the bending portion is electrically bent.
In the electric bending endoscope disclosed in Japanese Unexamined Patent Application Publication No. 2-159243, a bending operation device unit is integrally formed by connecting, to a main frame as a main frame member and a subframe, the motor as the bending operation means, a sprocket as a rotator for the stretch operation which transmits the motor's driving force to the bending operation wire, and the entire bending and stretch mechanism forming portions such as a transmission gear train. Further, the bending operation device unit is enclosed in the operating portion.
Similarly to the electric bending endoscope disclosed in Japanese Unexamined Patent Application Publication No. 2-159243, Japanese Unexamined Patent Application Publication No. 4-256724 discloses an electric bending endoscope in which a bending operation device unit is integrally formed by connecting, to a main frame and the like, a bending and stretch mechanism forming portions and the bending operation device unit is enclosed in the operating portion. The electric bending endoscope disclosed in Japanese Unexamined Patent Application Publication No. 4-256724 accomplishes an object of the present invention to provide the electric bending endoscope which can accurately sets a locking state and a free state with the compact size, light weight, and simple structure.